One radical and intriguing possibility for improving the efficiency and effectiveness of the health care system is to use the computer as an "intellectual" or "deductive" instrument -- a consultant that is built into the very structure of the health care system and augments the abilities of physicians and paramedical personnel. A number of research projects aimed at realizing parts of this goal have been initiated in the medical community. We propose to support these projects with software and expertise for the representation of knowledge, inquiry and explanation, integrative and administrative mechanisms for problem solving, decision analysis, and model-based decision making. We make specific proposals for collaborative research on cancer management, digitalis dosage computation, acid/base electrolyte therapy, taking the present illness, and patient record monitoring.